Recently did a hard reset on the LG L80 Dual D380 as it worked slowly and the battery was quickly discharged.
I will describe the order of actions:
1) We’ll turn off the phone.
2) Press the volume down and the power button, when the picture appears holding the volume button, release the power button and back press.
3) The reset menu appears with the volume buttons selected “YES” and the power button confirm “OK”, the second question similarly select “YES” and “OK”.
The phone will reboot and the user data will be cleared and reset to the factory settings, you will have to wait a little, done.